Sprue cleaning mill



Get. 11, 1960 R. JOOSS ETAL 2,955,305

SPRUE CLEANIINC; MILL Filed April 12, 1957 INVENTORj Rfl/VHOL D .10085 6 NO MWMJ l9 TTOPNE 15- BY LAW/ffA/Ci f. HAJRD/NG.

2,955,305 SPRUE CLEANING MILL Reinhold Jooss, Cleveland, Ohio, and Lawrence F. Harding, Detroit, Mich, assignors to The C. 0. Bartlett & Snow Company, Cleveland, Ohio, a corporation of Ohio I Filed Apr. 12, 1957, Ser. No. 652,395

1 Claim. (Cl. 15-90) This invention relates to a special form of tumbling 'mill, known as a sprue mill. for cleaning gates, risers,

fins and other sprue before charging the same into a. cupola to recover the metal therein. As is well known, the sprues and the like often are heavily encrusted with mold sand, the presence of which is obviously objectionable in the cupola, and the function of the sprue mill is to separate such sand from the metal in a continuous process.

Briefly, the mill comprises a hollow cylinder preferably supported at an inclination to the horizontal and rotated on its axis. The material is fed into such cylinder at the elevated end of the same and in passing to the lower discharge end it is tumbled to remove sand encrustation from the metal pieces and also to break up any large core lumps which might have been included in the feed. The cleaned metal passes out through the lower end of the cylinder, while the sand grains are discharged through perforations in the cylinder wall near such end. The rotating cylinder or barrel is quite large, for example, having a length on the order of thirty feet and a diameterin excess of five feet.

A certain amount of loose or very easily dislodged sand is usually present in the feed to the mill, and as the amount of such waste sand in the charge increases relative to the amount of metal, the cleaning of the latter be comes progressively less efiicient. That is, actual .practice has demonstrated that excessive sand in the mill has a cushioning eifect on the tumbling action, whereby the cleaning of the metal is impaired.

The new mill is accordingly provided with an additional sand discharge at the feed end. Such further discharge means is effective to drain off waste sand, as such, substantially as fast as it enters the mill, whereby the cleaning is fully accomplished at normal rates notwithstanding the inclusion of large amounts of loose sand. Thus no special attention or supervision of the feed is necessary for proper operation. This feature is of particular significance in large foundries, such as in the automotive industry, where the proportion of waste sand is apt to be quite high.

Other objects and advantages of the present invention will become apparent as the following description proceeds.

To the accomplishment of the foregoing and related ends, the invention, then, comprises the features hereinafter fully described and particularly pointed out in the claims, the following description and the annexeddrawings setting forth in detail certain illustrative embodiments of the invention, these being indicative, however, of but a few of the various ways in which the principle of the invention may be employed.

In said annexed drawings:

Fig 1 is a side elevation of a sprue mill constructed in accordance with our invention;

Fig. 2 is a transverse section as viewed from the plane of the line 2-2 in Fig. 1;

United States Patent() Patented Oct. 11, 1960 Fig. 3 is a further transverse section taken on the plane of the line 3--3 in Fig. 1; and

Fig. 4 is a fragmented section illustrating, on an enlarged scale, a cylinder wall formation.

Referring now to the drawing in detail, the mill comprises a cylindrical shell or barrel 10, which is open at assemblies 14, with the latter being positioned a predetermined distance above the door by standards 15. The ring 12 is similarly supported on trunnion rolls 16 held in axle and bearing assemblies 17 and positioned above the floor by a base 18. The base stand 18 is preferably of lesser vertical extent than the standards 15, whereby 'the shell is inclined to the horizontal as illustrated.

A girt gear 19 encircles the shell and in mesh with the same is a pinion 20 driven by an electric motor 21, through a conventional speed reducer 22. Such equipment, supported on a further base 23, of course forms a drive mechanism for rotating the cylinder on its inclined axis. Thrust rolls, not shown, will be employed at the sides of one of the riding'rings to limit axial movement of the cylinder, in conventional manner.

The elevated end 24 is the feed end of the cylinder, and a transversely rounded delivery chute 25 extends a short distance into the same for receiving the sprues to be cleaned and directing the same into the mill. Any suitable loading arrangement can be used, for example, the mill can be loaded from pivoting cars, with a skip hoist 'or other conveyor means, or with lift truck dumpboxes.

the same, through therotating shell. A series ofperforations 27 is provided in the shell'in a section closely adjacent the upper feed end, such perforations extending completely about the periphery, and this perforated section is enclosed by a curved housing 28 having end walls 29 and downwardly convergent extensions 30 of its circumferential wall. The series of perforations 27, as shown in the drawing,.form a perforate wall section of the cylinder of limited axial extent, with the outer end of the thus formed perforate wall section being spaced inwardly from the feed end of the cylinder a small distance which is clearly less than the internal diameter of the cylinder. The downwardly convergent extensions 30 form a downwardly open exit or discharge from the curved housing 28 enclosing this perforate Wall section of the cylinder.

At the lower or discharge end 31 of the mill, the shell is provided with a further series of perforations 32 and an encircling housing 33 likewise having a lower chute portion 34, the shell rotating within the two such housings. A belt conveyor 35, suitably guided and supported by rollers some of which are shown at 36, extends beneath the shell, between side plates 37 and arranged commonly to receive discharge from the two housings 28 and 33. It will be recalled that the lower discharge end of the shell is open and, to receive material passing from the same, there is a transversely extending conveyor 40', which may be of oscillating or other suitable type, with one side of its upper course just beneath and slightly overlapped by the lower shell end.

In operation, the rotating barrel receives the charge of sprues 'or the like through-the inclined" feed chute and any waste sand included therein is quickly expelled through the perforations 27. This sand is collected'in the housing 28 and delivered by the chute portion thereof tothebelt conveyor 35. The metal. parts, now free of ..orperforations 32 near' the discharge end arid onto the sameconveyor 35, which will. convey the sand to a suit- :able waste storage area. The now cleaned metal parts are discharged out such end of the cylinder and deposited on the conveyor 40 which transports them to a cupola or aplace of storage.

The discharge end housing33 has been shown provided with an upper. port'38 for connection to a blower operative to'suck air from the cylinder. This will produce air flow into the cylinder at both ends and-is desirable to prevent the escape of dust into the foundry; if desired,

.the housingZS may be similarly provided with a port and connected to the exhaust system. To increase the life of the shell, the'same may be lined with inner wear-resistantbars 39, as illustrated in Fig. 4, these being replaceable.

-It will accordingly be seen that this sprue mill is capable of handling large quantities of material incontinuous operation wtih the by-pass -forlfree sand provided: by the .feed end discharge assembly greatly enhancing the fiiciency of-the device, the initialsandremoval ensuring that the metal pieces are jarred sufficiently by the tumbling to knock. ofi encrusted mold sand. As indicated, the cylinder isv usually inclined, but it can obviously be operated in horizontal position as well, in which case the build-up of material near thefeed end causes the mass to move along the cylinder, with the time-of passage through the latter being increased.

The conveyors described are of course particularlysuscep'tible to change, withdifierent types and arrangements beingusable as desired or best suited to meet particular material-handling situations. For. example, instead of one sand conveyor extending axially beneath the cylinder, two belt or other type conveyors can be disposed generally transversely of the cylinder respectively to receive the sand as discharged from the two housings.

Other modes of applying the principle of the invention may be employed, change being made as regards the detailsdescribed, provided the features stated in thefollowing claim or the equivalent of such be employed.

We, therefore, particularly point out and distinctly claim as our invention:.

A mill for cleaning sprues and the like of mold sand, comprising a hollow cylinder having feed and discharge ends, means supporting said cylinder for rotation on its axis at an inclination toi th'e' lior-izontal and with its feed end uppermost, drivemeansfon thus rotating the cylinder, means for delivering a charge of the sprues and the like to be cleaned a to the :cylinder at such feed end, a. first 'series of sand. dischargetopeiiings in the cylinder-wall closely adjacent 'the feed end for discharge therethrough of loose sand included in the charge of the material, said first seriesof-sand discharge openings forming a perforate wall section of the cylinder of limited axial extent, with the end ofithe-thus formed perforate wall section close to the feed end of the cylinder being spaced inwardly from the latter a small distance which is less than the internal diameter of a cylinder, whereby loose sand in the feed is extracted through said first series of san'd'discharge openings before the material passes on through the rotating cylinder and is tumbled therein to separate the adherent sand, a second series of wall openings closely adjacent the discharge end of the cylinderfor removal of the sand separated from the sprues by the tumbling action, the cleaned sprues passing out the discharge end, said cylinder being imperforate between said'first and second series-of openings in the wall thereof, collector means associated with each series of openings for containing the sand discharged through the same, and means for removing the sand from said collector means separately from such discharge of the cleaned sprues.

References Cited in the file of this patent UNITED STATES PATENTS Re. 14,266 Bryan Mar. 6,.1917 951576 "Price Mar. 8,"19I0 2,122,545 'Windle July 5, 1938 2,427,388 Curran --Sept. 16,1947 2,523,258 Ransohofi Sept. 19,1950 "2,600,206 "Christensen June 10,1952

FOREIGN PATENTS 144,073 Australia Jan. 25, 1951 

